Advanced Laboratory in Physical Chemistry
This lab is designed for teaching advanced experimental techniques in physical chemistry during the last semester of B.Sc. studies, and it is mostly performed in various laboratories at the school of chemistry using equipment that is used for contemporary research.
The experiments are performed by pairs of students, where each pair performs 3 experiments out of the list appearing below during the semester.
The faculty members responsible for the lab are:
- Scanning Probe Microscopy (AFM/STM)
Abstract: This lab teaches the operation principles of Atomic Force Microscope (AFM) and Scanning Tunneling Microscope (STM). The experiment is performed in the lab of Prof. Gil Markovich.
The AFM scans the surface of a sample, and based on forces acting between the surface and a scanning tip, it is possible to obtain a topographic map of the surface with atomic scale resolution.
The STM obtains the surface topography by maintaining a tunneling current between a metallic tip and a conducting sample.
In this lab the AFM will be used to image samples produced in a research project on metal nanowires.
- Time Correlated Single Photon Counting (TCSPC)
Abstract: This experiment, performed in the lab of Prof. Dan Huppert, probes the significant chemical changes occurring upon excitation of a solvated molecule to an excited electronic state. The observed change is a change in the pKa value of the molecule, i.e., a change in its acidity. Molecules experiencing such a change are called photo-acids. The experiment teaches the basics of optical spectroscopy, with emphasis on the absorption and fluorescence spectroscopies. Fluorescence decay times will be measured using the TCSPC technique. In this experiment we will correlate the results from TCSPC measurements and fluorescence spectra to the change in the pKa value of the molecule 8-Hydroxypyrene-1,3,6-trisulfonic acid, which is a common photo-acid.
- Laser Spectroscopy
Abstract: This experiment, performed in the lab of Prof. Sergey Cheskis, exposes the students to tools and techniques used in modern laser spectroscopy. The topics addressed in this experiment are:
- Basic principles of laser operation
- Spectrographs and monochromators
- Intracavity Laser Absorption Spectroscopy (ICLAS)
- Fiber Laser Intracavity Absorption Spectroscopy (FLICAS)
- Point Contact and Molecular Junctions
Abstract: This experiment deals with fabrication methods, characterization and electrical measurements of molecular junctions. The experiment is divided in three parts. The first part teaches the photolithography technique, which is the main method used for fabrication of microelectronic devices. This part is performed in the clean-room at the center for nanoscience and nanotechnology. In the second part, the electromigration method for creating point-contact and molecular junctions will be introduced. This part is performed at the lab of Prof. Yoram Selzer and includes electrical characterization of the junctions. The third part teaches about scanning electron microscopy (SEM) and will be used to characterize the samples produced in the previous parts.
- Raman Spectroscopy
Abstract: This experiment teaches an optical measurement technique based on interaction of light with vibrational energy levels in materials in a process named Raman scattering. In this experiment, performed in the lab of Prof. Ori Cheshnovsky, the students learn the theoretical principles of the technique and the details of the experimental system, consisting of a microscope, laser light source, spectrograph and sensitive light detectors. The system is used to characterize various materials, including single grapheme layers and carbon nanotubes. In addition, the students monitor the temperature in electronic devices by measuring the population of different vibrational energy levels. This lab provides knowledge about research tools that are important for optics industry and research.
- Nuclear magnetic resonance (NMR)
Abstract: This experiment is designed to teach the physical aspects of NMR research. The lab complements the courses on basics of NMR and NMR applications in chemistry and medicine. Unlike the use of NMR for organic chemistry teaching, where analysis of the chemical shift spectra is the focus, here the emphasis is on measurement methods. The first meeting is used to study the NMR basics and at the end of this meeting a simple one-dimensional NMR spectrum is obtained. In the second week relaxation measurements are taught and performed and the third week is used to teach advanced topics that may change from time to time, such as: dynamic NMR, magnetization transfer, two-dimensional NMR, diffusion measurements.
- Langmuir-Blodgett Films
Abstract: In this experiment the Langmuir-Blodgett (LB) technique is used to prepare mono-molecular films. Those films are made of amphiphilic molecules (having a hydrophilic head and hydrophobic part. These films are prepared at the air-water interface. When spread at low enough concentration, these molecules, due to the different nature of their two parts, will be trapped at the interface, having the hydrophilic part dissolved in the water and hydrophobic residue in the air. Two-dimensional compression experiments will be performed on these trapped molecules in the LB instrument and by measuring the compression isotherms, phase transitions of the films will be observed and analyzed.
- X-ray Diffraction
Abstract: This lab is aimed at providing basic structural crystallography knowledge on single crystal as well as powder x-ray diffraction. The lattice diffraction phenomenon will be studied together with the determination of lattice symmetry from the diffraction pattern. This lab will address modern chemical crystallography, supramolecular chemistry crystallization methods, metal-organic frameworks (MOFs) and solving crystal structure. The lab will start with solvothermal crystallization of MOFs. The ligand to be used is trimesic acid combined with different metals. Laser diffraction off a two-dimensional crystal will be used to illustrate electromagnetic wave diffraction and the relation between the lattice spacings and diffraction spot spacings. Diffraction patterns of powders and single crystals of KCl, NaCl, and KBr will be used to calculate the unit cell dimensions in each case. Diffraction data collected for one of the prepared metal-organic crystals will be used to solve for the structure of the crystal including methods to improve the accuracy of the crystal structure determination. The students will also get to know the crystallographic data base, the Cambridge Structural Database (CSD).